Extended Data Fig. 2: The extracted contact resistance Rc and benchmark.
From: Sb-contacted MoS2 flash memory for analogue in-memory searches
(a) Output characteristic curves of Sb/Au Ohmic contact and Cr/Au Schottky contact devices. When using Cr/Au as contact electrodes, there exists an unavoidable Schottky barrier due to the strong Fermi level pinning at the contact interface, which usually induces non-linear output characteristic curves. In comparison, the Sb/Au contact device not only shows linear output characteristic curves, but also much larger output current. (b) Transfer characteristic curves of a typical TLM with channel length LCH ranging from 200 nm to 500 nm and VD = 1 V. Inset shows scanning electron microscope image of the Sb/Au contact devices with a TLM structure. MoS2 film was patterned into a strip with a width of 1.5 μm. Scale bar: 2 μm. (c) Rc extraction using the TLM method under different carrier densities. The y-intercept represents 2Rc = 800~1400 Ω μm, suggesting a Rc ranging from 400 Ω μm to 700 Ω μm at different carrier densities ranging from 0.19 ×1013 cm−2 to 0.77 ×1013 cm−2. (d) Rc as a function of carrier density n2D (n2D = Cox (VG – Vth)/q) for monolayer MoS2 with various contact metals or semimetals in the literature. The grey dashed line represents the quantum limit for Rc, πh/(4q2kF) ≈ 0.036(n2D)−0.5 kΩ μm, where h is Planck’s constant, q is the elementary charge, kF is the Fermi wavevector. The state-of-the-art Sb/Au-MoS2 FET was reported to approach the quantum limit in 2D semiconductor contacts26. We first reported the Sb/Au-MoS2 flash memory with ultra-small contact resistance, while at a lower carrier density, surpassing most metal contact FETs at a similar carrier density.
